Superoxide radical (O2) is produced by granulocytes for bactericidal purposes, but is also intimately involved in the inflammatory process. This project will investigate the roles of superoxide in inflammation and the pharmacologic activity of the scavenging enzyme superoxide dismutase as an anti-inflammatory agent. The physiologic roles and the chemical structure of a newly discovered superoxide-dependent chemotactic factor from plasma will be studied. Additional studies will examine the possible roles of calcium and the calcium-dependent regulatory protein, calmodulin, in the process of leukocyte activation.